Rinnai Tankless Water Heater Error Code 59: How to Fix It

Medium 30-60 minutes Medium Severity Verified June 2026
Summarize with ChatGPTSummarize with ClaudeSummarize with Perplexity Add as Preferred Source on Google
Error Code
59
Brand
Rinnai
Product Type
water_heater
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Error code 59 on your Rinnai tankless water heater indicates a short circuit in solenoid valve 5. This valve controls gas flow, so a short can prevent the heater from firing properly. This guide will help you diagnose and fix the issue safely.
Ad

Tools You'll Need

How to Fix Error Code 59

  1. Power Off the Heater

    Always turn off gas and electricity before servicing. Failure to do so may cause electric shock or gas leak.

  2. Locate Solenoid Valve 5

  3. Inspect Wiring and Connectors

  4. Test Solenoid Valve with Multimeter

    Be careful not to touch the terminals with your bare hands while measuring.

  5. Replace Solenoid Valve 5 if Faulty

    Gas work may require a professional. If you are not comfortable working with gas, call a technician.

  6. Reassemble and Test

Parts You May Need

Rinnai Gas Solenoid Valve (compatible with your model)
Check Price on Amazon
Rinnai Gas Solenoid Valve (compatible with your model)
Check Price on Amazon
Rinnai Gas Solenoid Valve (compatible with your model)
Check Price on Amazon
Rinnai Gas Solenoid Valve (compatible with your model)
Check Price on Amazon
Ad

When to Call a Professional

If you are not comfortable working with gas lines or electricity, if testing shows no wiring issues but error persists, or if the control board may be faulty, call a licensed Rinnai technician.

Frequently Asked Questions

What does Rinnai error code 59 mean?
Error code 59 means solenoid valve 5 (part of the gas valve assembly) has a short circuit. This prevents the water heater from igniting properly.
Can I still use my water heater with error code 59?
No. The heater will not operate safely. The error indicates a gas valve issue that could lead to unsafe operation. Turn off the unit and address the problem immediately.
Is it safe to replace the solenoid valve myself?
If you are experienced with gas appliances and have the right tools, it is possible. However, gas connections require care. If unsure, hire a professional.
How much does it cost to fix error code 59?
If DIY, the solenoid valve part costs around $30-$80. Professional service can cost $150-$300 including labor.
What tools do I need to diagnose error code 59?
A multimeter, screwdrivers, and a socket wrench set. Optionally, contact cleaner for connectors.

Related Error Codes